This invention relates generally to self-propelled crop harvesting machines having a header suspended forwardly from the frame thereof to harvest crop material from the ground, and more particularly, to an adjustment mechanism associated with the header flotation springs to permit an on-the-go adjustment of the weight of the crop harvesting header resting on the ground.
Typically, self-propelled crop harvesting machines are provided with a wheeled frame supporting drive apparatus to power the movement of the machine over the ground and a crop harvesting header forwardly disposed to engage standing crop material to initiate the crop harvesting process. Such headers are movably connected to the frame and are provided with a flotation mechanism interposed between the frame and the header to support a portion of the weight of the header from the frame, the remainder of the header's weight usually resting on the ground.
Generally, such flotation mechanisms comprising a spring or a grouping of springs associated with laterally opposite sides of the header. By mounting the springs on a draw bolt apparatus, the operative length of the spring or spring assembly can be varied. As one skilled in the art will readily realize, the stretching of a spring results in the exertion of a force that is linearly proportional to the length of the spring. Such draw bolt mountings adjust the length of the spring and provide a setting for the amount of flotation force to be applied to the header. While the flotation setting can be varied while the machine is stationary, it would be preferable to provide a mechanism for adjusting or varying the flotation force while the crop harvesting machine is operatively moving over the ground.
Such a on-the-go adjustment of the flotation force will allow the operator of the crop harvesting machine to adjust the flotation force in response to the conditions he finds in the field as he is traversing across the ground. For example, should the operator encounter a soft spot in the field while he harvesting standing crop material, he could increase the flotation force to lighten the weight of the header resting on the ground and prevent the header from digging into the soft spot, which could cause damage to the header and possibly harm the crop being harvested. Accordingly, it is desirable to provide a mechanism for adjusting the flotation setting for a crop harvesting header while the header is in operation.